During refueling operations, such as aerial refueling operations for example, a tanker aircraft supplies fuel to a receiver aircraft while in-flight. One approach to aerial refueling is known as probe-and-drogue refueling. In a probe-and-drogue system, the tanker aircraft extends a flexible hose having a refueling coupler (commonly referred to as a drogue) disposed at a distal end of the hose. The receiver aircraft has a probe, which the receiver aircraft maneuvers into engagement with the drogue. After the probe couples to the drogue, the tanker aircraft supplies fuel to the receiver aircraft provided the receiver aircraft remains within a predetermined fuel transfer zone.
During an aerial refueling operation, the receiver aircraft is generally responsible for maneuvering relative to the tanker aircraft to couple the probe on the receiver aircraft with the drogue of the tanker aircraft. Once coupled, the receiver aircraft attempts to maintain a position within the fuel transfer zone so that the receiver aircraft can receive fuel at a safe distance of separation from the tanker aircraft.
Currently, several pieces of information are required by a pilot of the receiver aircraft when refueling the receiver aircraft during flight. Examples of such information include the distance between the drogue and the tanker aircraft (e.g., fuel transfer zone), a status of the drogue (e.g., engaged with the receiver aircraft), and a status of the tanker (e.g., ready to provide fuel). The flexible hose includes markings at various locations along a length of the hose to indicate the boundaries of a refueling range and the fuel transfer zone. The tanker includes a lighting system, installed on the fuselage of the tanker aircraft that provides indication of the status of the tanker. Accordingly, to successfully perform a refueling operation, the pilot of the receiver aircraft must monitor the status of both the signal lights on the tanker and the markings on the hose to determine the tanker refueling system status and the position of the receiver aircraft relative to the fuel transfer zone in order to maneuver or maintain the receiver aircraft position appropriately to receive fuel from the tanker safely. The pilot monitoring the status of both the signals lights on the tanker and the markings on the hose has many drawbacks including that the markings on the hose may be challenging for the pilot to observe when operating under low-light conditions such as, for example, during night operations and/or during inclement weather. Additionally, the pilot has to continuously shift focus between the hose markings and the tanker lighting system during the refueling operation. Furthermore, at night, the markings on the hose can sometimes be confused with lighting glare giving a false indication. Unfavorable sun angles during daytime and in-contact turns may impose additional challenges to the receiver pilot's workload and safe operations.
What is needed is a centralized and discernible system that provides all information currently available to the receiver aircraft to be displayed for a pilot of the receiver aircraft on a display, such as a head up display (HUD) or a helmet display, so that the pilot only needs to focus on a single point enabling the information to be deciphered quickly and precisely in order to take appropriate actions in a timely manner.